the mission -- to kill the world's most wanted made, osama bin laden. >> the death of bin laden marks the most significant achievement to date in our nation's effort to defeat al qaeda. >> most have heard the incredible details of the bin laden compound raid, but little has been revealed about the intense, months' long dl deliberation that led to the decision to act. so how was the decision made? who was told? how did they weigh the options? tonight, we will ask the man tasked by the president to synthesize the intelligence, analyze the assessments and run the decision-making process, to act in a sense as gatekeeper of this monumental decision. i sat down with national security adviser tom donilon in secretary of war suite of the eisenhower executive office building. >> when you come into the white house, has the trail for osama bin laden gone cold? >> when we came into office, the beginning of 2009, the trail had gone cold. we really hasn't had a good case to his whereabouts since he was at tora bora in 2001. >> so what does the president say at that point? he tells leon panetta, get